Quick-acting clamp.



No. 735,941. PATENTED AUG. 11,1903.

A. M. COLT. QUICK ACTING CLAMP.

APPLICATION FILED JAN. 12, 1903.

I0 MODEL wuxu Wiznsfiesl fnvenzo WM W lz i 'ormsys FNITED STATESPatented August 11, 1903.

PATENT ()FFICE.

QUICK-ACTING CLAMP.

SPECIFICATION forming part of Letters Patent N 0. 735,947, dated August11, 1903. Application filed January 12, 1903. SerialNo-138l623. (Nomodel.)

T0 ctZZ whom it may concern.-

Be it known that I, ALVA M. COLT, a citizen of the United States,residing at Batavia, in the county of Genesee and State of New York,have invented new and useful Improvements in Quick-Acting Clamps, ofwhich the following is a specification.

This invention relates more particularly to a quick-acting clamp of thatkind in which a shank or bar is provided with a jaw slidably mounted onthe same and having grippingfaces to bind 0n the shank to hold thesliding jaw at any desired point on the shank and an opposingclamping-plate which is moved toward the sliding jaw by a cam-lever,screw, or other device.

The object of the present invention is to provide a desirable,effective, and durable clamp in which the sliding jaw will at all timeswhen in use firmly grip the shank and not slip.

In the accompanying drawings, Figure 1 is a side elevation of a clampembodying the invention. Fig. 2 is a fragmentary longitudinal sectionthrough the shank and sliding jaw. Fig. 3 is a transverse sectionthrough the shank, showing the sliding jaw in plan. Fig. 4 is afragmentary elevation showing a slightly-different means for operatingthe clamping-plate. 7

Like letters of reference refer to like parts in the several figures.

A represents a straight bar or shank which is provided at one end with afixed arm or portion B,extending forwardly from the shank substantiallyat right angles thereto. The shank or bar is of U or trough shape incrosssection, having separated parallel side walls which are ofconsiderable width and are connected only at their rear edges by a backwall b, so that the hollow or open side of the trough is at the front.The shank is preferably made of sheet metal and while comparativelylight has great stiffness and strength.

0 represents the sliding jaw or arm. This jaw is provided at its frontend with a fiat bearing face or portion 0 for the work and is providedat its rear endwith a hole D, through which the shank passes and whichsubstantially conforms in shape to the external crosssectional shape ofthe shank. The sliding jaw is also provided with a tongue E, whichextends rearwardly into the hole D of the jaw toward the back wall ofthe shank and between the side walls thereof, as shown in Figs. 2 and 3.The rear end face e of the tongue and the rear face 01 of the hole inthe jaw are so formed (see Fig. 2) that when the front end of thesliding jaw is tilted or pressed slightly away from the fixed arm of theclamp the gripping-faces will grip or bind on the opposite faces of therear wall of the shank and the jaw will be firmly held against movementaway from the fixed arm, while by tilting or pressing the front end ofthe sliding jaw toward the fixed arm the sliding jaw releases its holdon the shank and can he slid along the same. The rear gripping-faces ofthe tongue E and hole D are relatively long and bear for a considerableportion of their length against the rear wall of the shank when grippingthe same, thus reducing wear on these faces and increasing the longevityand durability of the device.

Frepresentsaclamping-plate which is provided with a flat bearing-faceopposed to the bearing-face of the sliding jaw. The clamp- I ing-plateis connected to the inner end of a stem f, movably supported on thefixed arm of the clamp. The 'plate is preferably connected to the stembya ball-and-socketjoint, so that the plate can tilt on the stem andalways bear fiat against the work. In the construction shown in Fig. 1the stemfslides longitudinally in a bearing-hole in the fixed arm of'theshank and is operated to clamp and release the work by a cam-lever G,pivoted on a pin g, secured on a lug on the fixed arm of the clamp, andhaving a camshaped flange which engages between the outer end of thestem and a finger g thereon. 'When the work is placed between theclamping-plate and the sliding jaw and the latter slid along the shankinto contact with the work, the camlever is operated to force theclamping-plate against the work and clampthe latter firmly between thesliding jaw and clamping-plate. The shank carrying the clam ping-platecan be operated by any other suitable means. For instance, as shown inFig. 4, the shank H is screw threaded and works in a screwthreaded holein the fixed arm and is provided at its outer end with an operating-headh.

Only the rear faces (1 and e of the hole and tongue of the sliding jawgrip or bind on the shank, and the front wall 01 of the hole is out ofcontact with the front edges of the side walls of the shank, and as thetongue is of considerable length the leverage of the sliding jaw ingripping the shank is great and a very firm hold results, even shouldthe work being clamped bear against the sliding jaw at the front edge ofthe shank. This is important, for in using the clamp with some classesof work it is desirable to place the work directly against the straightfront edge of the shank to hold it in place and prevent it from bucklingwhen pressed or clamped between the sliding jaw and clamping-plate.

I am aware that a clamp of this type in which the sliding jaw isprovided with opposite side gripping-lugs engaging between side flangeson the shank is old; but in said clamp the gripping-lugs are necessarilysmall and have very small gripping-faces, which' soon wear and renderthe device ineflicient. It is also old to provide the sliding jaw with arearwardly-projecting loose tongue which is held in contact with theshank by a spring. This construction is objectionable on account of thesmall disconnected tongue, which is apt to be detached and lost, and theemployment of the spring, which is liable to be broken. It is also oldto provide the sliding jaw with a tongue entering a slot in the frontface of the shank and gripping against opposite flanges at the front ofthe shank. This clamp is not certain in use, as the gripping-points areat the front of the shank, and if the work bears on the jaw near theshank the leverage is so short that the jaw will not hold.

I claim as my invention- The combination of a shank having separatedparallel side walls connected by a back wall, a jaw projecting forwardlyfrom and slidable on said shank, said jaw having a hole through whichthe shank passes and a rigid tongue projecting rearwardly in said holebetween the side walls of said shank and adapted to hear at its rear endagainst the back wall of said shank to bind the latter between the rearend of said tongue and the rear wall of said hole in the jaw, aclamping-plate arranged opposite to said sliding jaw, and means formoving said clamping-plate toward and from said sliding jaw,substantially as set forth.

Witness my hand this 6th day of January, 1903.

ALVA M. COLT.

Witnesses:

EDWARD J. HOGAN, H. W. SKELLEY.

